Solid diazo salts



Patented May 31, 1938 UNITED STATES PATENT OFFICE SOLID DIAZO SALTS poration of Delaware No Drawing. Application November 27, 1936, Se-

rial No. 113,083. In Germany May 21, 1932 Claims.

The present invention relates to new solid diazo salts; more particularly it relates to diazo salts containing a free amino group and corresponding probably to the general formula:

whenrein Y stands for halogen, n and p stands f or one of the numbers 1 and 2, and wherein the benzene nucleus may be further substituted.

This application is a continuation-in-part of our co -pending U. S. patent application Serial No. 671,590, filed May 17, 1933 which has matured into Patent 2,067,132.

The diazo salts may be obtained by diazotizing unilaterally lA-diaminobenzenes, halogenated in the nucleus and being free from sulfonic acid or carboxylic acid groups, i. e. by treating the said 1,4-diaminobenzenes with the quantity of mineral acid and nitrous acid, necessary for diazotizing one amino group, and by precipitating the diazo compounds, thus obtained, in the form of the different kinds of arylsulfonates.

Morgan and Cleage (cf. Journal of the Chemical Society, 113, (1918), pages 590 and 596) have transformed 2,6-dichloro-lA-diaminobenzene in dry acetone solution into 2,6-dichlorobenzene-4-diazo1-imine by the action of nitrous anhydride. The product, thus obtained, is very unstable. It was not separated in a solid form but, after its formation, it was at once acetylated in the acetone solution and thereby identified.

It could not be foreseen that halogenated 1,4- diaminobenzenes could be transformed in a smooth reaction into aminodiazonium salts in the presence of mineral acid and it could, furthermore, not be foreseen whether these monodiazo compounds could easily be precipitated and whether they would be stable enough for being used on an industrial scale as dyeing salts.

As is known, it is not possible to perform the mono-diazotization of para-phenylenediamine in a technical manner. Biilow (cf. Berichte der Deutschen Chemischen Gesellschaft, 29, (1896), page 2285) describes the unilateral diazotization of nitro-para-phenylenediamine; but it could not be concluded from this literature reference that it would be possible to transform halogenated 1,4-diaminobenzenes into a mono-diazo compound.

All these diazo salts possess a very good stability, even at higher temperatures. It is, therefore, possible to furnish the dyer, for whom it is difficult or at least laborious to carry out the mono-diazotization of the diamines, with monodiazo compounds in a stable form ready for use.

These new solid diazonium salts which may be diluted with the usual admixtures and adjusted to the usual commercial form, are of especial 5 valuein the ice color industry.

The following examples serve to illustrate the invention, but they are. not intended to limit it thereto, the parts being by weight:

(1) 187 parts of 2-bromo-1,4-diaminobenzene 1 are diazotized in 145 parts of sulfuric acid of 78% strength and 2800 parts of water at 10 C. to 15 C. with a solution of 72 parts of sodium nitrite in 300 parts of water. To the diazo solution, there are added 740 parts of an aqueous 5 solution of 41% strength of free 1,5-naphthalene disulfonic acid. The 1,-5-naphthalene disulfonate separates in a crystalline form and is worked up in the usual manner. It possesses a very good stability.

By rep-lacing 1,5-naphthalenedisulfonic acid by 2,6-naphthalenedisulfonic acid, there is obtained in an analogous manner the corresponding 2,6- naphthalenedisulfonate.

(2) 177 parts of 2,6-dichlo-ro-1,4-diaminobenzene are diazotized in 270 parts of hydrochloric acid of 32.1% strength and 3500 parts of water at 10 C. to 15 C. with a solution of 72 parts of sodium nitrite in 300 parts of water. To the diazo solution, there is added a solution of 260 parts of the sodium salt of para-chlorobenzenesulfonic acid in 500 parts of water of about 35 C. Thereby, the diazonium-para-chlorobenzenesulfonate separates and is worked up as usual. It corresponds probably to the following formula:

wherein n and 10 stand for one of the numbers 1 and 2, Y stands for halogen, Z for one of the group consisting of hydrogen, halogen and alkyl, and R means a member of the group consisting of radicals of the benzene and naphthalene series, being very stable and easily soluble in water.

2. The solid diazo salts corresponding to the general formula:

wherein n and 11 stand for one of the numbers 1 and 2, Y stands for halogen, Z for one of the group consisting of hydrogen, halogen and alkyl and R means a member of the group consisting of radicals of the benzene and naphthalene series, being very stable and easily soluble in water.

3. The solid diazo salts corresponding to the general formula:

wherein n and 1) stand for one of the numbers 1 and 2, and R means a member of the groupconsisting of radicals of the benzene and naphthalene series, being very stable and easily soluble in water;

4. The solid diazo salt corresponding to the formula:

7 Br SOaH HaNONr-SO:

being very stable and easily soluble in water.

5. The solid diazo salt corresponding to the formula:

HINQNFSOBGCI being very stable and easily soluble in water.

KARL SCHNITZSPAHN. WILHELM KOCH. 

